CVE-2023-54030 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
io_uring/net: don't overflow multishot recv
Don't allow overflowing multishot recv CQEs, it might get out of hand, hurt performance, and in the worst case scenario OOM the task.
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Analysis
by VulDB Data Team • 12/28/2025
The vulnerability identified as CVE-2023-54030 resides within the Linux kernel's io_uring subsystem, specifically affecting network operations involving multishot receive functionality. This issue represents a critical flaw in how the kernel handles asynchronous I/O operations, particularly when multiple receive operations are processed simultaneously through the io_uring interface. The vulnerability manifests when the system attempts to process multishot receive completions in the completion queue, leading to potential resource exhaustion scenarios that can severely impact system stability and performance. The flaw directly relates to how the kernel manages completion queue entries for multishot receive operations, creating a condition where excessive or uncontrolled completion queue entries can accumulate and overwhelm system resources.
The technical root cause of this vulnerability stems from inadequate bounds checking and resource management within the io_uring network subsystem. When multishot receive operations are executed, the kernel allocates completion queue entries to track the progress of these asynchronous operations. However, the implementation fails to properly enforce limits on the number of completion queue entries that can be generated, allowing for potential overflow conditions. This design flaw enables malicious actors or even legitimate high-throughput applications to generate an excessive number of completion queue entries, which can rapidly consume system memory resources. The vulnerability specifically affects the net subsystem where io_uring handles network I/O operations, making it particularly dangerous in high-performance network environments where multishot receive operations are commonly utilized.
The operational impact of CVE-2023-54030 extends beyond simple performance degradation to encompass potential system instability and resource exhaustion. When the multishot receive completion queue entries overflow, the system may experience significant performance degradation as the kernel struggles to manage the excessive completion queue entries. In the most severe scenarios, this overflow condition can lead to out-of-memory (OOM) situations where the kernel's memory management system is overwhelmed, potentially resulting in system crashes or forced reboots. The vulnerability is particularly concerning for systems running high-throughput network applications that rely heavily on io_uring's multishot receive capabilities, as these applications could inadvertently trigger the overflow condition through normal operation or could be exploited by attackers to cause denial-of-service conditions. The impact is exacerbated in environments where multiple concurrent connections or high-volume data transfers are common, as the accumulation of completion queue entries can rapidly escalate.
Mitigation strategies for CVE-2023-54030 should focus on implementing proper bounds checking and resource management within the io_uring subsystem. System administrators should ensure that all Linux kernel updates are applied promptly, as this vulnerability has been resolved in recent kernel versions through patches that enforce proper limits on multishot receive completion queue entries. The fix implemented addresses the specific overflow condition by introducing appropriate bounds checking mechanisms that prevent excessive allocation of completion queue entries during multishot receive operations. Organizations should also monitor their network applications that utilize io_uring for multishot receive functionality to identify potential exposure to this vulnerability. Security teams should consider implementing resource monitoring and alerting for unusual completion queue entry patterns, as this could serve as an early indicator of potential exploitation attempts. The vulnerability aligns with CWE-129 Input Validation and CWE-770 Allocation of Resources Without Limits or Throttling, and may be categorized under ATT&CK technique T1499.004 for resource exhaustion attacks, highlighting the need for comprehensive system hardening and proper resource management practices.